Harness assembly for a nasal mask

ABSTRACT

A harness assembly for a nasal mask for communicating breathable gas to a patient&#39;s airways, for example, in the administering of CPAP or like breathable gas delivery treatments, includes a cap portion adapted to engage, in use, the occipital region of the skull. The cap portion includes a connector at each end. The harness assembly also includes a pair of upper and lower straps, each of the straps extending between one of the cap connectors and the nasal mask. The harness assembly grips the head in a region substantially fixed relative to the face and, as such, tension of the straps is not substantially affected by head movement.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.08/982,755, filed Dec. 2, 1997 now U.S. Pat. No. 6,494,207, allowed, thespecification and drawings of which are incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates to a harness assembly for a nasal mask.

The invention will be described with reference to a harness assembly fora nasal mask fitted to the head of a wearer for communicating breathablegas to a patient's airways, for example in the administering ofcontinuous positive airway pressure (CPAP) treatment. However, theinvention is not limited to this particular field of use and is equallysuited for masks used in assisted respiration or mechanical ventilation.

BACKGROUND OF THE INVENTION

CPAP treatment is administered when a person is asleep It is thereforecrucial that nasal CPAP masks be securely fastened to the wearer's head.Leaks occurring due to mask movement caused by gross body motion duringsleep can result in the efficacy of CPAP treatment being defeated. Aneffective seal of the mask cushion to the patient's face is, in part, afunction of the mask design, and is also a function of the correcttension in the harness being maintained. Under-tensioning results in aloose mask and poor seal. Over-tensioning can lead to discomfort for thewearer. All of these problems can lead to patient noncompliance.

A prior art nasal mask and harness arrangement is taught in U.S. Pat.No. 5,243,971 assigned to the University of Sydney. The nasal mask issecured to a wearer's head by a harness comprised of an upper strap anda lower strap, each of which is secured to a frame of the nasal mask.The upper portion of the frame includes a pad that engages the wearer'sforehead. The frame farther carries a nasal cushion that, in use of themask, sealingly engages the wearer's nose and face. The frame alsocarries a mask body to which is connected a flexible conduit for thedelivery of breathable gas to the mask and thereafter to an entrance tothe patient's airway.

A problem with this arrangement is that the upper and lower straps aremade from an elastic or resilient material which lose elasticity withtime and become loose fitting about the wearer's head. Furthermore,movement of the wearer during sleep, may cause sliding movement of thestraps to the point where the mask can become loose and leaks occur.

Also, the tightening of either the upper or lower strap tends to pivotthe mask thereby altering the tension of the other strap makingcomfortable and correct adjustment difficult and time consuming.

Other harness arrangements, such as that shown in U.S. Pat. No.5,542,128 in the name of Lomas, include an upper strap around the headand a lower strap around the neck. This arrangement exacerbates thetensioning problem discussed above as rocking of the head moves the facerelative to the neck thereby altering the tension of the straps,especially the neck strap.

Another prior art arrangement is disclosed in published AustralianPatent Application No. 32914/95 in the name of Buckley-Mendez.

It is important to distinguish nasal masks for the administration ofCPAP treatment from respirators or breathing apparatus that arecharacterised by full face cover and are intended to simultaneouslydeliver air to the nose and mouth of a conscious and mobile patient. Incontrast, CPAP treatment primarily occurs during sleep when the wearerof a nasal mask is mostly immobile and cannot tolerate the discomfort ofrespirators or breathing apparatus for want of arousing from the sleepstate.

The present invention is directed to overcoming, or at leastameliorating, one or more of the disadvantages of the prior art.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect, the present invention provides a harnessassembly for a nasal mask for communicating breathable gas to apatient's airways, the harness assembly includes a cap portion adaptedto engage, in use, the occipital region of the skull, said cap portionincluding a connection means at each end, and a pair of upper and lowerstraps, each of the straps extending between one of the cap connectionmeans and the nasal mask.

The harness assembly according to the invention grips the head in aregion substantially fixed relative to the face and, as such, straptension is not substantially affected by head movement.

Preferably, the cap connection means are adapted to allow the capportion to pivot substantially independently of the mask and straps.

The connection means are desirably disposed, in use, adjacent the earsof the wearer. Most desirably, they are just above the ears.

The cap connection means are preferably further adapted to allow eachstrap to move substantially independently of the other straps.

Each strap is preferably length adjustable.

Desirably, the cap portion, in use, covers the occiput of the wearer.

In an embodiment, the cap portion engages and/or grips the curved regionof the occiput.

In another embodiment, the cap portion includes an opening throughwhich, in use, the occiput at least partially protrudes.

The connection means desirably also allows the straps to slide normallyrelative to the direction of the strap.

In a particularly preferred embodiment, the connection means are in theform of substantially D-shaped members. In this embodiment, the capportion is connected to the straight portion of the D-shaped members andthe upper and lower straps are each respectively connected to the upperand lower curves of the D-shaped members.

In another preferred embodiment, the connection means is in the form ofa triangular member. In this embodiment, the cap ends and the upper andlower straps each respectively engage a side of the triangle.

In another particularly preferred embodiment, the connection means is inthe form of a yoke shaped member having a inner bar and a pair of outerbars each angled slightly with respect to the inner bar. In thisembodiment, the cap portion is connected to the inner bar and the upperand lower straps are each connected to one of the outer bars.

In yet another embodiment, the connection means are in the form ofsubstantially “C” shaped members. In this embodiment the lower strapsconnect to the head of the C, the upper straps to the middle and the capportion to the base. In this embodiment, the cap portion and the upperstraps can be manufactured from a single component.

The connection means is preferably produced from plastics, elastomers,composites, laminates or other like materials.

The cap portion and straps can be produced from fabric or like materialsor laminates thereof. The cap portion may also be moulded to snugly fitthe head, in particular to replicate the shape of the occiput, bythermoforming, fabric darting, or joining two or more pieces along anon-straight seam.

In a second aspect, the invention provides a nasal CPAP mask and harnessassembly, the assembly includes a mask with a nasal cushion and maskbody connected to the harness assembly of the first aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention now will be described withreference to the accompanying drawings, in which:

FIG. 1 is a front perspective view of a harness assembly according to afirst embodiment of the invention;

FIG. 2 is a rear perspective view of the harness assembly shown in FIG.1;

FIG. 3 is a front perspective view of a harness assembly according to asecond embodiment of the invention;

FIG. 4 is a rear perspective view of the harness assembly shown in FIG.3;

FIG. 5 is a front perspective view of the harness assembly according toa third embodiment of the invention;

FIG. 6 is a rear view of the harness assembly as shown in FIG. 5;

FIG. 7 is a side view of a D-shaped coupling of the first embodiment ofthe present invention; and

FIG. 8 is a side view of a triangular shaped coupling used in a fourthembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the FIGS. 1 and 2, there is disclosed a harness assembly 40according to a first embodiment of the invention. The harness assembly40 is shown, in use, securing a nasal mask 42, which is suitable forCPAP treatment, to a human head 43. A suitable mask is shown in FIG. 3.The nasal mask 42 includes a mask body and a mask cushion attached tothe mask body. The mask cushion engages the patient's face. A couplingtube is connected at one end with the mask body and at the other end toa socket into which can be received a gas delivery tube (not shown).

The harness 40 includes a cap portion 44 which is adapted to engage thelower rear region of the wearer's skull. The cap portion 44 issubstantially semi-circular in shape when laid flat. When worn, thelower most portion 46 of the cap portion 44 covers and grips theoccipital region of the wearer to facilitate securely locating the capportion during use.

The cap portion includes a connection means at each end which in thefirst embodiment shown in FIGS. 1 and 2 is in the form of a D-shapedcoupling 48. A pair of upper straps 50, of which only the left-hand isshown in FIG. 2, extend between the coupling 48 and an upper portion 52of the nasal mask. Similarly, a pair of lower straps 54 extend betweenthe coupling 48 and a lower portion of the mask 56.

In the embodiment shown, each of the straps are length adjustable, byvirtue of hook and loop connectors 58. In another embodiment, not shown,the straps are of constant length and the harness is produced in anumber of sizes to suit various size heads.

The connection of the straps to the D-shaped coupling member 48 allowseach of the straps 50 and 54 to pivot with respect to each other and thecap portion 44. The coupling member 48 also allows the straps and capportion to slide slightly in a direction normal to the longitudinaldirection of the strap or cap portion. As the D-shaped coupler allowsthe upper and lower straps and the cap portion to all move independentlyof one another then an improved harness is provided as movements of oneof the above parts, caused by, for example, repositioning of thewearer's head during sleep, will riot unduly affect the others therebyproviding a more securely fitted nasal mask.

The location of the mask 42 is also unaffected when the position of capportion 44 is independently moved for best fit.

Further, as no part of the harness assembly engages the neck, headmovements, such as rocking, which alter the face to neck distance, donot affect strap tension resulting in more secure and comfortablefitting mask.

A second embodiment of the harness assembly is shown in FIGS. 3 and 4 inwhich like reference numerals are used to indicate like features. Inthis embodiment the connection means is in the form of a yoke shapedcoupling 60. The yoke 60 includes an inner bar 62 connected to an upperand lower bar 64 and 66 respectively. The upper and lower bars areangled slightly with respect to the inner bar so as to be substantiallynormal to the longitudinal axis of the upper and lower straps 50 and 54.Once again, the yoke 60 allows the straps 50, 54 and the cap portion 44to move independently of one another.

A third embodiment of the harness assembly is shown in FIGS. 5 and 6.Once again, like reference numerals are used to indicate like features.In this embodiment the connection means are in the form of C-shapedmembers 70 disposed, in use, above the wearers ears. A cap portion 72includes an opening 74 through which the occiput protrudes to assist insecurely locating the cap portion.

The opening 74 improves the maintenance of the cap portion 72 in thecorrect position. Further, the opening 74 reduces heat build up underthe cap portion 72, compared to these shown in FIGS. 1 to 4.

Although the invention has been described with respect to preferredembodiments, it will be appreciated by those skilled in the art, thatthe invention may be embodied in many other forms.

As an example, the cap portion 72 of the third embodiment may be usedinstead of the cap portion 44 of the first and second embodiment.

1. A harness assembly adapted to secure a mask to a face comprising apair of upper and lower straps and a cap portion with a D-shapedcoupling member joining the upper and lower straps to the cap portion,wherein: the D-shaped coupling member is constructed and arranged sothat the upper and lower straps and the cap portion are coupled to theD-shaped coupling member while still allowing independent movementrelative to one another, and the upper and lower straps and the capportion are made from fabric, and the cap portion is structured toconform to the patient's occiput in use, and a portion of said capportion that is made of said fabric has a surface that engages with asurface of the coupling member.
 2. The harness assembly according toclaim 1, wherein the fabric is provided as a portion of a laminate. 3.The harness assembly according to claim 1, wherein the upper and lowerstraps are provided to discrete upper and lower portions of the D-shapedcoupling member.
 4. The harness assembly according to claim 1, whereinthe D-shaped coupling member includes a generally linear leg coupled tothe cap portion and a curved portion supporting the upper and lowerstraps.
 5. The harness assembly according to claim 1, wherein the upperand lower strap portions have first and second ends defining arespective closed loop portion each fixedly connected to the D-shapedcoupling member.
 6. A CPAP nasal mask assembly comprising: a nasal maskhaving a frame carrying a nasal cushion; a slotted connector provided toeach lateral side of the frame; and the harness assembly of claim
 1. 7.A harness assembly adapted to secure a mask to a face comprising a pairof upper and lower straps and a cap portion with a coupling memberjoining the upper and lower straps to the cap portion, wherein: thecoupling member is constructed and arranged to allow the upper and lowerstraps and the cap portion to slide slightly in a transverse directionnormal to a longitudinal direction of a respective one of the upperstrap, the lower strap and the cap portion, the upper strap is providedto a first discrete portion of the coupling member and the lower strapis provided to a second discrete portion of the coupling member, thefirst and second discrete portions being spaced from one another, theupper and lower straps and the cap portion are made from fabric, and thecap portion is made of a material structured to conform to a patient'socciput in use, and a portion of said cap portion that is made of saidfabric has a surface that engages with a surface of the coupling member.8. The harness assembly according to claim 7, wherein at least one ofthe upper and lower straps is constructed from a material structured toconform to a patient's head in use.
 9. The harness assembly according toclaim 8, wherein the fabric is provided as a portion of a laminate. 10.The harness assembly according to claim 7, wherein the coupling memberis substantially D-shaped.
 11. The harness assembly according to claim7, wherein the coupling member is substantially triangularly shaped. 12.The harness assembly according to claim 7, wherein the coupling membercomprises a yoke including an inner bar coupled to the cap portion andupper and lower bars coupled to the upper and lower straps,respectively.
 13. The harness assembly according to claim 12, whereinthe upper and lower bars are angled slightly with respect to the innerbar.
 14. The harness assembly according to claim 12, wherein each of theupper and lower bars is open ended to define a slot to receive a loopedportion of the upper and lower straps, respectively.
 15. The harnessassembly according to claim 12, wherein the inner bar is associated withan open slot to receive a looped portion of said cap portion.
 16. Theharness assembly according to claim 15, wherein the cap portion and eachof the upper straps are formed from a single piece of material.
 17. Theharness assembly according to claim 7, wherein the coupling membercomprises a C-shaped member adapted to be positioned above the patient'sear in use.
 18. The harness assembly according to claim 17, wherein theC-shaped member includes a first slot for the upper strap, a second slotfor the lower strap and a third slot for the cap portion.
 19. Theharness assembly according to claim 7, wherein the coupling memberincludes an upper portion coupled to the upper strap, a lower portioncoupled to the lower strap and a rear portion coupled to the capportion.
 20. The harness assembly according to claim 7, wherein theupper and lower straps are independently slidable in the transversedirection.
 21. A CPAP nasal mask assembly comprising: a nasal maskhaving a frame carrying a nasal cushion; a slotted connector provided toeach lateral side of the frame; and the harness assembly of claim
 7. 22.A harness assembly adapted to secure a mask to a face comprising a pairof upper and lower straps and a cap portion with a coupling memberjoining the upper and lower straps to the cap portion, wherein: thecoupling member is constructed and arranged to allow the upper and lowerstraps and the cap portion to slide slightly in a transverse directionnormal to a longitudinal direction of a respective one of the upperstrap, the lower strap and the cap portion, and the upper strap isprovided to a first discrete portion of the coupling member and thelower strap is provided to a second discrete portion of the couplingmember, the first and second discrete portions being spaced from oneanother, wherein the lower strap has a first end forming a closed loopportion fixedly connected to the coupling member and a second endstructured to be adjustable in length.
 23. A harness assembly adapted tosecure a mask to a face comprising a pair of upper and lower straps anda cap portion with a coupling member joining the upper and lower strapsto the cap portion, wherein: the coupling member is constructed andarranged to allow the upper and lower straps and the cap portion toslide slightly in a transverse direction normal to a longitudinaldirection of a respective one of the upper strap, the lower strap andthe cap portion, and the upper strap is provided to a first discreteportion of the coupling member and the lower strap is provided to asecond discrete portion of the coupling member, the first and seconddiscrete portions being spaced from one another, wherein the upper straphas a first end forming a closed loop portion fixedly connected to thecoupling member and a second end structured to be adjustable in length.24. A harness assembly adapted to secure a mask to a face comprising apair of upper and lower straps and a cap portion with a coupling memberjoining the upper and lower straps to the cap portion, wherein: thecoupling member is constructed and arranged to allow the upper and lowerstraps and the cap portion to slide slightly in a transverse directionnormal to a longitudinal direction of a respective one of the upperstrap, the lower strap and the cap portion, and the upper strap isprovided to a first discrete portion of the coupling member and thelower strap is provided to a second discrete portion of the couplingmember, the first and second discrete portions being spaced from oneanother, wherein the cap portion has a strap portion provided directlyto the coupling member.
 25. A harness assembly adapted to secure a maskto a face comprising a pair of upper and lower straps and a cap portionwith a D-shaped coupling member joining the upper and lower straps tothe cap portion, wherein: the D-shaped coupling member is constructedand arranged so that the upper and lower straps and the cap portion arecoupled to the D-shaped coupling member while still allowing independentmovement relative to one another, wherein the cap portion includes astrap defining a closed loop portion fixedly connected to the D-shapedcoupling member.
 26. A harness assembly for a nasal mask forcommunicating breathable gas to a patient's airways, the harnessassembly comprising: a cap portion adapted to engage an occipital regionof the patient's skull in use, the cap portion including an upper strapportion and a lower strap portion that cooperate to define an openingthrough which the occiput region at least partially protrudes in use;and side straps extending forward of the cap portion, each of the sidestraps including a hook and loop fastener, wherein: the side strapsextend superior to the patient's ears in use, the cap portion and sidestraps are produced from fabric material, and each said side strapincludes a first end having a non-variable length portion positionedadjacent a respective end of the cap portion and a second end structuredto be threaded through a slotted connector associated with the nasalmask whereby each said side strap portion is adjustable in lengthrelative to the nasal mask via the hook and loop fastener.
 27. Theharness assembly according to claim 26, wherein each said side strap andthe cap portion are formed as an integral unit.
 28. The harness assemblyaccording to claim 27, wherein each said side strap and the cap portionare formed as a single piece.
 29. A CPAP nasal mask assembly comprising:a nasal mask having a frame carrying a nasal cushion; a slottedconnector provided to each lateral side of the frame; and the harnessassembly of claim
 26. 30. The harness assembly according to claim 26,wherein each said side strap and the cap portion are formed as acontinuous unit.
 31. The harness assembly according to claim 30, whereinsaid continuous unit is formed from a single piece.